Citation: Erikstad, K. E., P. Fauchald, H. Sandvik and T. Tveraa (2006)
Parental effort and recruitment to the breeding colony in the Atlantic Puffin:
inferences based on a manipulation experiment [abstract of a symposium talk given by
H. Sandvik at the XXIVth
International Ornithological Congress in Hamburg].
Journal of Ornithology, 147 (Supplement 1), 37.
[what’s a doi?].
Adult survival is often assumed to be the single most important
life-history trait in long-lived species such as seabirds. While it is probably true –
and robustly grounded in prevailing theory – that adult survival is more important
than annual fecundity, other traits, such as survival to maturity, have been neglected.
Because of high ages at first reproduction and small cohort sizes, this parameter is not
easily studied, and very few studies have attempted to do so.
From shorter-lived birds, it is known that initially small differences in
individual quality at fledging may be amplified into large differences in post-fledging survival.
It is therefore of major interest to quantify the effect that fledgling quality has on subsequent
survival of seabirds during the pre-breeding stage and, ultimately, recruitment.
In order to address this question, we carried out a manipulation experiment with
breeding Atlantic Puffins Fratercula arctica. We manipulated parental effort by swapping
chicks of different age between nest burrows. In this way, we obtained breeding pairs that faced
either prolonged or reduced breeding periods. From life-history theory it can be predicted
that seabird parents are not willing to fully compensate increasing demands of offspring.
Accordingly, the manipulation of parental investment resulted in significant differences in
fledgling quality. By using experimental manipulation, we were furthermore able to control
for other, potentially confounding variables, such as the genetic quality of the parents.
Before fledging, all chicks were weighed, measured, and individually colour-ringed.
Subsequently, the colony was monitored for both the return of established breeders and the
recruitment of new breeders. Relying on ten years of observation after the experiment, and
using capture-mark-recapture modelling, we have now been able to analyse the effect of the
experiment on the natal recruitment of Puffins.
Related publications: Elaborations of this talk appeared in
Auk and Ecology.